The present invention relates to rotating electrical machines (e.g., electrical motors and generators) and in particular to a rotating electrical machine employing axially extending interdigitated pegs.
Electrical motors and generators share similar structures of an electrically interacting stator and rotor and may be collectively termed “rotating electrical machines,” Conventional rotating electrical machines may be roughly divided into “electromagnetic” devices exploiting magnetic fields and/or change in inductance (reluctance) between moving parts, and “electrostatic” devices exploiting electrical fields and change in capacitance between moving parts.
Electrostatic rotating electrical machines have a number of advantages over conventional electromagnetic rotating electrical machines including the elimination of magnets and costly rare earth materials, significant weight from ferrous materials, and high current copper windings.
Electrostatic machines are commonly found in micro-scale, micro-electromechanical systems (MEMS) which permit extremely small gaps between rotor and stator elements allowing high capacitance and high electrical fields. For larger scale rotating machines, for example, those providing integer horsepower and larger outputs (macro-scale), the physical gap between the stator and rotor may be one to three orders of magnitude larger than that for MEMS machines. This larger gap requires higher applied voltages typically in the tens or even hundreds of thousands of volts for comparable torque. These high voltages normally require ultrahigh vacuum containment vessels to prevent arcing between stator and rotor components.
The simultaneous requirement of minimizing the gap (tolerances) between stator and rotor components and using high voltage driving power can present significant manufacturing challenges in manufacturing macro scale electrostatic motors.